Significance and Use 4.1 The rating increases as the impact sound attenuation of the floor ceiling structure increases. The rating can be used by architects, builders, and specification and code authorities for acoustical design purposes in building constructions. 4.2 The rating strictly only applies to excitation by the standard tapping machine defined in Test Methods E492 and E1007. It does not deal with low frequency sounds below 100 Hz that are typically generated below lightweight joist floors when they are walked on. Nor does it deal with the squeaking, crunching or rattling sounds that can occur in joist construction when elements in the construction are loose and occupants walk on the floor. 4.3 This classification shall only be used with one-third octave band data.Scope 1.1 This classification provides a method for determining a rating that can be used to compare the levels of impact noise generated by a standard tapping machine and transmitted through different floor-ceiling assemblies. 1.2 The name given to the rating is assigned by the test method that invokes this classification. 1.3 This classification is applicable only to one third octave band impact noise data obtained using the standard tapping machine described in Test Methods E492 and E1007. 1.4 Test methods that invoke this classification include: 1.4.1 Test Method E492 – the single-number rating is called impact insulation class (IIC). 1.4.2 Test Method E1007 – the single-number ratings are called apparent impact insulation class (AIIC), impact sound rating (ISR), and normalized impact sound rating (NISR). 1.4.3 Test Method E2179 – the single-number rating is called the change in impact insulation class (ΔIIC). 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
